DNA methylation is critically involved in the control of chromatin structure and gene expression. There are data in the literature suggesting that alcohol may influence DNA methylation patterns. Therefore, we are carrying out studies on the localization and expression of DNA methyltransferase (MTase), the enzyme responsible for DNA methylation, focusing on brain tissues. MTase mRNA and enzyme levels are being studied in different adult brain regions, as well as during development. The regulation of MTase in the adult brain by ethanol and acetaldehyde, by steroids, and other factors are being determined. As a sensitive measure of possible effects on methylation at a specific genomic loci, we will examine effects of ethanol on the expression of imprinted genes where transcriptional silencing is known to be mediated by DNA methylation. The expression of DNA methyltransferase in the adult brain led to the hypothesis that this enzyme may play a role in DNA repair. Therefore, we have initiated a series of studies on the capability of DNA repair processes by adult neurons. We have found that adult brain neurons can carry out select types of DNA mismatch repair, including G:T mismatch repair. In addition, we have shown that the adult brain contains enzymes that address oxidatively damaged DNA as well. Formerly titled: "Expression and Regulation of DNA Methyltransferase in the Mammalian Brain"